Magneto



F. A. HOYT.

MAGNETO.

APPLICATION F|LED APR. 28, 1920.

1,398,485. Patented Nov. 29, 1921.

4 SHEETS-SHEET 1- INVENTOR A TTORNEY F. A; HOYT.

MAGNETO.

APPLICATION FILED APR.28. 1920.

1,398,485. Patented Nov. 29, 1921.

4 SHEETSSHEET 2- HT BE A INVENTOB F. A. HOYT.

MAGNETO.

APPLICATION FILED APR.28,1920.

1 ,398 ,485. Patented Nov. 29, 1921.

4 SHEETSSHEET 3.

1718 1718 1718 1718 fil 1718 40' g 47 Z9 4 y 0\ r/vmvm 3f? er A TTORNEY F. A. HOY T.

MAGNETO.

APPLICATION FILED APR.28,192'0.

1,398,485. Patented Nov. 29, 1921.

4 SHEETS-SHEET 4.

a 404 '3 INVENTOR 447 i MAM 02 A TTORNE Y winding as is UNITED STATES new JERSEY.

Application filed April 28,

To all whom it may concern.

Be it known that I, FREDERICK A. HoY'r, a citizen of the United States, residing at East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Magnetos; and I do hereby declare the following to be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which it appertains to make and use the same.

y invention consists in the novel features hereinafter described, reference being had to the accompanying drawings which illustrate one embodiment of the invention selected byme for purposes of illustration, and several modifications thereof, and the said invention is fully disclosed in the following description and claims.

y invention relates more particularly to the manufacture of magnetos for double spark ignition systems, for internal combustion engines, which are constructed to produce from a single secondary coil, two sparks in each cylinder of the engine. In magnetos of this kind, the secondary winding, instead of having one end connected to the primary customary in ordinary magnetos, is entirely disconnected from the primarv winding, and each end of the secondary winding isconnected with the ignition a certaln amount circuit. Suitable distributing mechanisn1 connects the secondary winding at the proper times with two spark plugs located in each c linder of the internal-combustion engine, parks are produced simultaneously at the spark gaps ofboth plugs. In'the manufacture of such double spark ignition magnetos in which but one secondary winding is employed, it has been found practically impossible heretofore to wind a secondary coil upon the armature of the magnetowith. sufliclent strength of insulation to stand up sat-v isfactorily under long continued use. After of'use it is found that the insulation of the secondary, winding becomes defective and the coil iS'short-circuited, rendering the magneto inoperative. It has also been found that the insulation is broken through in practically the same portion of the winding in each 'case,'that is to say between layers of the secondary winding, usually near the inner portion of the colladjacent to the primary winding over Specification of Letters Patent.

ondary winding,

tential increases in the PATENT oFFIcE.

MAGNETO.

I Patented Nov. 29, 1921. 1920. Serial No. 377,168.

which the secondary winding is wound. If suificlent insulation be placed between the first few layers of the secondary windin to safely wlthstand the full potential whic is built up duringtheoperation of the magneto, it becomes lmpossible to wind sufiicient wireon the armature to give good results, and 1t has been practically fore to use this type of spark ignition systems. As a result of conslderable experiment I have discovered that this serious diiiiculty in double spark magnetos can be entirely remedled by inserting a suitable condenser in connection with the secondary winding of the magneto armature, and my, invention consistsbroadly in providing such a conmagneto in double ondary winding is incorporated in the magthat it has not neto, it being understood been found possible under ordinary circumstances to. install such a condenser in or upon the armature itself within the. limitations of neto,-- which has resulted uniformly in the breaking down of the insulation of the secis due to the fact that the high resistance in the ignition circuit, due to the presence therein of the double spark gaps, and the consequent high {potential and results eventually in the generation of a secondary current of such high voltage as to jump the insulation at such points usually adjacent to the inner end portion of the coil, and short circuit the secondary winding, and that the effect of the condenser for the ondary winding, which I the secondary condenser, of opposite polarity to be set up as the posecondary winding, and which at the moment of sparking acts term hereafter to neutralize to a certain extent thefcurrent of opposite polarity in the secondary windimpossible therethe manufacture of the very steep potential sec- I is to cause a charge ing, and thereby decrease the steepnem of the potential front, thus protecting the secondary winding against .short-circuiting. Regardless of theory, however, and as a practical fact, I have discovered that by the employment of a condenser in conjunction.

with the secondary winding of a magneto for double spark ignition, the: d1fliculty heretofore experienced is entirely overcome,

secondary winding,

and the armature may be wound successfully with a normal amount of insulation on the and that the magnetos constructed in accordance with my invention are as efficient and durable for-double spark ignitionas the ordinary magnetos used for single spark ignition.

In carrying out my invention practically,

I ma employ a single condenser for the secon ary winding, or I may em ploy two condensers for the secondary winding. -Owing to the limitations of magneto structure,

prefer toemploy a single condenser for. the secondar the current collectors for the high tension or secondary current, and the distributor, and this construction has been found to be highly practical and eflicient.

In the accompanyin drawin .1 have illustrated the preferre manner In which I have contemplated embodying my inven- Fig. l is a detail'illustrating one means of supporting the dielectric member of the condenser for the secondary winding.

, Fig. 2 is a front view of the magneto; with the housing of the periodic interrupter removed.

Fig. 3 is a perspective view-of the mag net'o with a portion of the'magnets on one side of the same removed for the purpose of showing the condenser for the secondary winding to better advantage.

Fig. 4: is a schematic diagram illustrating the relation of the'partsof the magneto. Fig. 5 is a wiring diagram illustrating the ma neto and double spark ignition system.

ig. 6 is'a schematic drawing similar to Fig. 4, illustrating a modified form of con- U denser, which in this instance may be embodied in the secondary rotor or distributing' rotor ofthe magneto.

winding and tolocate it beed in the usual manner.

suitable means .ing each of the essence Fig. 7 is a view similar to Fig. 6 illustratin a further modification of the condenser em odied in. the stationary portion of the distributer.

Fig.8 is a schematic view similar to Fig. 7 illustrating another arrangement by which two condensers are provided in connection with the secondary winding.

Fig. 9 is a view similar to Fig. 8, also illustrating an arrangement in which two condensers are employed in connection with the secondary winding. v

Fig. -1O is a wiring diagram showing the magneto in which two condensers .for the secondary winding are employed.

In the preferred embodiment of my invention, which is illustrated in Figs. 1 to 5 inclusive l represents the frame of the -magn eto, in which is mounted the rotary armature 2 comprising the primary winding, indicated at 3,'and the secondary winding, indicated at 4. Thesecondary winding 15 'ungrounded and is wholly unconnected throughout its length with the primary winding; The primary winding is connectwith a circuit breaker or periodic interrupter indicated at 5, thepreferred' form of which is shown j in Fig. 2, and comprises a rotary part car ried by-the armature and provided with a 'fixed contact 6- and movable contact '7 carried by an L-shaped lever Shaving a fiber heel 9, for engaging suitable cams 10-'10 tacts 6 and 7 in a well known way. In the mafgneto herein shown the armature is wound so as to produce two sparks in each revolution of the same and accordingly two of thehcams" 10 are provided for this purpose, said cams-being mountedon a cam ring 11 so as to be rotatable by means of the timing lever 12 for the purpose of advancmg or'retarding the'spark, in the usual manner; 13 represents the usual condenser.

arranged in' connection with the primary winding and periodic interrupter, in theusual manner.

Means are provided for connecting each end of the secondary winding 4 with ahigh tension current distributing means. In the present instance I have shown two distributors each comprising a circular part, indicated at 14, 15 respectively,

and provided with the usual distributing contacts 16, of which'six are shown herein,

the magneto being arranged for firing a six-cylinder internal combustion engine, and

are provided for connectcontacts of each distributing spark plug in one of the cylinders, there being therefor two spark plugs in each cylinder, indicated at 17-18 respectively, in the diagram, Fig. 5. In conjunction with the distributor rings 1 preferably ring with a employ the usual distributerrotor, indicated for .separating the fixed and movable coneach other, this rotor armature and driven therefrom by means of engages a a p1nion-22 on the armature shaft, which gear wheel 23 on the rotor, the

gears being arranged to drive the rotor 19 with a high is concentric from the brush 27 Lee at a

words, of the armature of the magneto. One of the brushes, as the brush 20, is connected tension terminal rod 24 which with the rotor and is provided at its outer end with a spring actuated brush 25 for engaging a part connected with the high tension current collector 26 pro- Vided with a brush 27 for:- engaging the slip ring 28 on, the armature shaft. The slip ring is provided with two segments 29 and 30 insulated from each other, and one end of the secondary windin is connected to each of said segments. second high tension current collector is employed, indi cated at 31 provided with a brush 32 for engaging the slip ring on the side opposite and this current collector is connected preferably by a cable or wire 33 with a brush 34 arranged concentrically with the rotor 19 and engaging a metallic plate 35 connected with the distributer brush 21 so that each end of the secondary winding ,is connected with a separate distributer. The brush 34 is carried by a cap 37 detachably applied to the exterior of the distributer, in this instance being connected speed of one to three, or in other to and supported by the .exterior distributer sion terminal 24 and its brush 25. instance I have shown the condenser as ring 15;. 36 represents the usual field mag- .net or magnets surrounding the armature and united to the magnet framein the usual, or any preferred manner, and any suitable form or casing or casings may be employed to protect the parts of the magneto from dust and moisture.

In the preferred form of my invention the condenser for the secondary winding is located between one end of the secondary winding and the distributer connected therewith, and preferhblysurrounds the hi h tinn t 1s comprisingtwo metallic sleeves separated as glass or mica,

by a cylindrical body of dielectric material, and preferably glass. I prefer to form the inner of said sleeves, indicated at 40, integral with a disk 41, against the inner face of which the brush 25 bears, secured to a stem 42, which is screwed into or otherwise secured to the high tension terminal 26. The sleeve 40 and disk 41 forms a cup-shaped metallic member which assists in supporting the dielectric cylindrical body 43, which may be further supported at one end by engagement with the nut 44 on the inner end of the supportbeing located above the three revolutions of the rotor to one sleeve 40 and said cylinder, as shown in Fig.

1, for example, or'the nut 44n1ay be provided with a plurality of light spring fingers 46 in some instances, for flexibly holding the inner end of the dielectric sleeve, as indicated in Fig. 1*, in which the nut is indicated at 44 if desired. On the outside of the dielectric cylinder 43 is a metallic sleeve 47 which is conveniently formed as a split sleeve in order to allow for contractionand expansion, as illustrated for example in Fig. 3, the sleeve 47 being located in substantial alinement longitudinally with the inner sleeve 40. Means are provided for connecting the sleeve 47 with the other end of the secondary coil, and in this instance the sleeve 47 isshown as provided with a stud 48 connected by a cable 49 which extends through the dust cap of the machine and is fastened to the lower slip ring brush-holder 31. By this arrangement both sides of the secondary winding of the armature are connected to the condenser, one by means of the cable 49, just mentioned, and the other by the stem 42 and the collector brush. The operative effect of this construction will be clearly apparent from an examination of the schematic drawing shown in Fig. 4 (in which the connections from the distributersto the spark plugs are omitted) and the wiring diagram shown in Fig. 5, in which the entire multi-spark ignition system is illustrated. It will be readily seen that the effect of the condenser for the secondary winding is to prevent sparking between coils of'the secondary high the potential of the secondary or high tension current may be, and it has been found by practical experience with this apparatus that the use of this condenser in connection with the secondary winding effectively prevents impairment of theinsulation of the secondary winding, and permits of the manufacture of magnetos of this character withsecondary coils provided with the usual amount of insulation, in which the winding no matter how.

dangerof breakdown by short circuitin of the secondary winding is practically eliminated. It will also be noted that'the preferred construction, which I have described, is a very convenient one and permits the installation of the condenser for the secondary current with a minimum of change in the general construction of the magneto.

I wish it to be understood, however, that my invention may also be carried into effect and embodied in other ways, and in Flgs. 6 to 10 inclusive, I have illustrated. several which the condenser shown 1n which are entirely practicable Figs. 1 to 5 inclusive,

additional embodiments of my invention and eflicient, although I prefer the form illustrated in and heretofore described. Y

In Fig. 6 I have represented schematically a slight modification of my invention in condenser for the secondary winding is embodied in the rotor of the distributer and comprises two separate metallic plates 140 and 147-, between which I preferably arrange a dielectric plate 143 of glass, mica, or'otherv suitable material. The-plate 140 is connected with a high tension current distributing means 124 connected with the collector brush 127, the other metallic plate 147 being connected to the brush 134, which is connected by the cable 133 with the other collector brush 132, the other parts represented in Fig. 6 being given the same numerals as the corresponding parts in Fig. 4, with 100 added. In Fig. 6 I have indicated diagrammatically at 117-118 the spark plugs for one of the cylinders of aninternal combustion engine. The eiiect of the Fig. 6 will be identi- -cal with that shown in Figs. 1 to 5, in protecting the insulation of the secondary winding and preventing short circuiting between i the coils thereof.

In Fig. 7 I have represented, schematically, another slight modification of my in-' vention,

in which the condenser for the secondary winding is located upon a stationary portion the cap 237 which carries the high tension terminal brush 234, connected by the wire 'or cable 233 with the collecting brush 232. The conden'ser in this instance comprises a'pair of metallic disks 240-247 separated by an intermediate disk 243 of dielectric material. In this instance the disk 240 is connected with the brush 234 and the disk 247 is connected with the other collecting brush 227, in any desired way, as for example by an insulated wire, as indicated at 250. In this figure 224 represents the connection from one of the distributer brushes 220 to the collecting brush 227 and the brush 221 of the distributer will be connected to the terminal brush 234 in the usual manner. I have indicated, in Fi 7, the spark plugs for one cylinder at 21 218.

In some instances I may provide two condensers for the secondary winding, and in Fig. 8, for example, I have represented schematically a construction of magneto in which I have combined the form of condenser shown in Figs. 1 to 5, together, with thatillustrated in Fig. 7. In this instance the collecting brushes are indicated at 327 and 332, the brush 327 being electrically connected with the inner cylindrical metallic member 340 of the condenser, around which 18 placed the dielectric cylindrical body 3453,

of the distributer, as for example,

grounded, as indicated at 350, so as to place --it 1n electrical connection with the exterior metallic member 347 of. the other condenser, while the disk 340 is connected by the brush 334 and cable 333 with the collecting brush 332. The second .distributer brush 321 is connected to the terminal brush 334 inthe usual manner, and the spark plugs for one cylinder are indicated at 317 and 318.

Fig. 9 is a view similar to Fig. 8 and shows an arrangement in which two condensers are employed, one condenser being mounted in the distributer, and in this instance carried. on the distributer cap 437 and comprising the metallic plates-447 and 440, separated by the dielectric plate 443, the plate 447 being grounded, as indicated at 45 0, and the plate 440 being connected with the terminal brush 434, which is connected in the usual manner with the distributer brush 421, the terminal brush 434 being connected as heretofore described by the cable which comprises a pair of metallic 'pl'ates 440 and 447, separated by a dielectric plate 443. In this instance the plate 440 is connected by a wire 452 with the brush holder for the brush 427, and the plate 447 is placed in electrical connection with the plate 447 in any suitable manner as by grounding it, as indicated at 451.

Fig; 10 represents a small wiring diagram indicating the arrangement in which two condensers are arranged in conjunction with the secondary winding, the distributers being omitted and the spark plugs for a single cylinder only being indicated, for convenience; the reference characters indicated being the same as those in Fig. 9.

What I claim and desire to secure by Letters Patent is 1. In a high tension magneto electric machine, the combination with a field magnet, an armature provided with a primary winding and an ungrounded secondary winding, a' periodic interrupter in circuit with the pri-. mary winding, and a distributer for the high tension current, of acondenser for the secondary winding comprising a cup shaped metallic member, connected to one end of the secondary winding and to said distributer, a cylindrical dielectric member surrounding the said cup shaped member and an exterior cylindrical metallic member surrounding said dielectric member, the other end of the secondary winding being connected to said exterior metallic member of the condenser, and to the distributer.

2. In a high tension magneto electric machine, the combination with a field magnet, an armature provided with a primary winding and an ungrounded secondary winding, a periodic interrupter in circuit with the primary winding a distributer for the high tension current, a slip ring on the armature provided with segments each connected to one end of the secondary winding and collecting brushes and brush holders therefor, of a condenser for the secondary winding comprising a cu shaped member supported by one of said brush holders and electrically connected to the brush thereof, a cylindrical dielectric member surrounding the cup shaped member, and a cylindrical member surrounding the said dielectric member, and electrically connected to the other bru'sh, high tension circuit connections from each brush to the distributer, one of said connections extending into and engaging the inner end of the cup shaped member of said condeser.

3. In a high tension magneto electric machine for multi spark ignition purposes, provided with an ungrounded secondary winding, each end of which is connected with thedistributer by means of a slip ring, and separate brushes, a condenser for the secondary winding comprising a cup shaped metallic member supported by one of the brush holders, and electrically connected with the brush thereof, a cylindrical dielectric member surrounding'said metallic member, and an exterior cylindrical metallic member surrounding said dielectric member, the rotary portion of the distributer being provided with a high tension conductor extending into said cup shaped member and provided with a brush engaging the same, and the ex terior metallic member being provided with means forconnecting it with the other brush holder.

4. In a high tension magneto electric ma-. chine for multi spark ignition purposes, provided with an ungrounded secondary winding, each end of which is connected with the distributer by means of a slip ring, and separate Washer, a condenser for the secondary winding comprising a cup shaped metallic member supported by one of the brush holders, and electrically connected with the brush thereof, a cylindrical dielectric member surrounding said metallic member, and an exterior cylindrical metallic member surrounding said dielectric member, the rotary portion of the distributer being provided with a high tension conductor extending into said cup shaped member and provided with a brush engaging the same, and the exterior metallic member being provided with means for connecting it with the other brush holder, and yielding means interposed between the cylindrical dielectric member and its metallic support to allow for expansion and contraction.

5. In a high tension magneto electric machine for multi spark ignition purposes, provided with an ungrounded secondary winding, each end of which is connected with the distributer by means of a slip ring, and sepa rate brushes, a condenser for the secondary winding comprising a cup shaped metallic member supported by one of the brush holders, and electrically connected with the brush thereof, a cylindrical dielectric mem ber surrounding said metallic member, and an exterior cylindrical metallic member surrounding said dielectric member, the rota portion of the distributer being provided with a high tension conductor extending into said cup shaped member and provided with a brush engaging the-same, and the exteripr metallic member being provided with means for connecting it with the other brush holder, the exterior metallic member 95 of the condenser being split to allow for ex, pansion and contraction.

6. In a high tension magneto electric machine for multi spark ignition purposes, provided with an ungrounded secondary wind- 100 ing, each end of which is connected with the distributer by means-of a slip ring, and separate brushes, a condenser for the secondary winding comprising a cup shaped metallic member supported by}, one of the brush 105 holders, and electrically connected with the brush thereof, acylindrical dielectric member surrounding said metallic member, and an exterior cylindrical metallic member surrounding said dielectric member, the rotary 110 portion of the distributer being provided with a'; high tension conductor extending into said cup shaped member and provided with a brush engaging the same, and the exterior metallic member being provided 115 with means for connecting it with the other brush holder, the exteriormetallic member of the condenser being split to allow for expansion and contraction, and yielding means interposed between the dielectric member and 12 FREDERICK A. HOYT. 

